Hydraulic control system for road graders

ABSTRACT

A hydraulic control system for road graders wherein normal mechanical control clutches are replaced with control levers which operate hydraulic valves located outside of the operators compartment for the grader, and which in turn control hydraulic motors connected to existing gear boxes and rotary drives for the various grader operation.

0 limited States Patent [1 1 [111 3,759,333

Rivinius 1 Sept. 18, 1973 HYDRAULIC CONTROL SYSTEM FOR 2,192,439 3/1940 Gustafson 172 793 x ROAD GRADERS 2,870,551 1/1959 Thompson 3,700,044 10/1972 Berg 172/804 [76] Inventor: Theodore Rivinius, 1322 N. 4th St.,

Blsmarck 5850] Primary Examiner-Robert E. Pulfrey {22] Filed: Apr. 12, 1971 Assistant ExaminerStephen C. Pellegrino pp No 133 291 Attorney-Dugger, Peterson, Johnson & Westman [57] ABSTRACT [52] US. Cl 172/781, 172/785, 251/284 511 Int. Cl 1502f 3/12 A hydraullc Control System for road graders Wherem [58] Field of Search 172/781, 791, 790, normal mechanical control clutches are rePlaced with 172/793, 801404; 251/231 234 control levers which operate hydraulic valves located outside of the operators compartment for the grader, [56] References Cited and which in turn control hydraulic motors connected UNITED STATES PATENTS to existing gear boxes and rotary drives for the various grader operation. 3,593,806 7/1971 Gurries 172/793 X v 7 2,766,772 10/1956 Welty et a1. 251/284 X 4 Claims, 5 Drawing Figures nsssune 5 saunas l '3 Patented Sept. 18, 1973 2 Sheets-Sheet 1 wukaam INVENTOR. THEODORE mum/H Z WW yrmmffj Patented Sept. 18,1973 3,759,333

2 Sheets-Sheet 2 INVENTOR. 77/[000RE W/V/lV/US HYDRAULIC CONTROL SYSTEM FOR ROAD GRADERS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control systems for road graders or maintenance equipment.

2. Prior Art Road graders of course have been used for many years. U.S. Pat. No. 2,034,141 to Gustafson shows a machine with typical mechanical drives for operating the various components of the road graders. This type of machine is basically in use today even though the frame and other components of the road graders have undergone modifications, and the power of the graders has increased substantially.

Other types of graders have attempted to utilize all hydraulic controls using hydraulic rams and the like for operation, but these also have operating deficiencies that are objectionable.

One of the problems with the mechanical drive systems is that they are difficult to operate, lack precise control, and many times the clutches will kick-back against the operator making it extremely tiresome and sometimes even hazardous to operate.

SUMMARY OF THE INVENTION The present invention relates to a conversion system which replaces the mechanical clutches such as those shown in U.S. Pat. No. 2,034,141 with simplified hydraulic controls operating on the same standard mechanical drive systems to control various functions of a road grader. The control levers used in the present device operate hydraulic valves which in turn drive high torque, low speed hydraulic motors to power the existing driven accessories of the road grader. The present device thus presents a gang of control handles that can be mounted in the place of the conventional control gear box on mechanically operated graders, and which have rods extending to valves mounted exterior of the control cab. The valvesin turn are coupled from a source of hydraulic fluid under pressure to the hydraulic motors used for operating the existing drive gears for controlling the grader blade, a scarifier, wheel tilt and other motions conventional in a road grader.

In addition, the hydraulic valves used are modified to provide positive mechanical stops that will not break from the high force obtainable with the levers utilized with the present invention, and which thereby safe guard the operation of hydraulic valves and make conventional type production valves usable.

The control handles are mounted on a common I mounting member, and are easily actuated. The control rods or links extending to the hydraulic valves pass BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a typical road grader having controls made according to the present invention installed thereon;

FIG. 2 is a top plan view of the control portions of the device of FIG. 1;

FIG. 3 is a sectional view taken as on line 3--3 of FIG. 2;

FIG. 4 is a fragmentary side view of a typical valve showing the stop members made according to the present invention installed thereon; and

FIG. 5 is a top plan view of the device of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT A standard motor grader shown generally at includes a main frame 11 made in the usual manner, power drive wheels 12 and front steering wheels 13. The frame is of conventional design. A drawbar I4 is pivotally mounted to the front part of the frame 11, and the drawbar 14 in turn has a circle frame 15 rotatably mounted thereon. The circle frame supports a working blade 16 that engages the ground surface 17 to maintain or grade this ground surface. The circle frame 15 can be shifted laterally with respect to the grader frame in the conventional manner through a lateral shift gear box 20, acting through a link 21 to cross support member 22 on the mounting for the circle frame. The blade 16 and the circle frame is raised and lowered through lift links 23 actuated by control shafts 24 through levers 25. The control shafts 24 are powered by lift gear box assemblies 26 (there is one control shaft on each side of the frame 11). Operation of the gear boxes 26, either simultaneously or separately causes the circle frame and blade 16 to be raised or lowered or placed at a desired slope of cut.

In addition, of course the operator has a steering wheel 27 that operates a steering wheel shaft 28 to drive a steering gear 29 for turning the front wheels 13. The front wheels 13 have a wheel lean gear box which is conventionally used in the art, and this is operated through a drive shaft 33 to the wheel lean gear box illustrated in dotted lines at 34. The wheel lean mechanism permits leaning or tilting.

The circle frame 15 is mounted so that it can be rotated with respect to the drawbar 14 and member 22 about an upright axis to angle the blade 16 with respect to the normal direction of travel of the frame through the use of a gear box 35 mounted on the mounting drawbar 14, and driving the circle frame 15 in the usual manner.

In addition, a gear box illustrated in dotted lines at 36 can be used for operating a control linkage for scarifiers. The scarifier is not shown installed on thepresent grader but is a conventional unit utilized normally on motor graders.

An operators platform illustrated generally at 40 is mounted on the frame, and includes an upright divider frame member 41 at the forward portions thereof, and

as shown in dotted lines can have a cab housing 42 to enclose the operators platform.

The normal gear box assembly on the operators divider frame 41 for the operators platform has been removed, and a hydraulic control support assembly 45 has been mounted to the frame 41 in place of the normal mechanical clutches. The control assembly, as perhaps best seen in FIG. 2, comprises a bracket member 46, and this bracket member is attached to the frame 41 in a suitable manner. The bracket member 46 has a pair of side walls and a rear wall and the side walls mount a transverse shaft 47 (see also FIG. 3) and this shaft is mounted to suitable end support hubs or members 43. Shaft 47 in turn has a plurality of control handles mounted thereon. For example there is a right lift control handle 48, a left lift control handle 49, a scarifier control handle 50, a circle reverse or rotate control handle 51, a circle lateral shift handle 52, and a wheel lean control handle 53. Of course the control handles can be used for any of the various controls as desired. Each of the handles includes a separate hub member rotatably mounted on the shaft 47 and a lower extending lever portion, the lever portion is shown typically in FIG. 3 at 48A. The lower extending lever portions of each of the control levers is connected to a corresponding control link, numbered 338, 4&8, 56B, 51B, 52B and 53B. These links extend out through openings in the divider frame 41, and pass between the gear boxes 26,26 which are used for operating the lift link shafts 24.

A valve mounting bracket 55 is mounted to the frame It on the top thereof and ahead of the operators platform. The valve mounting bracket 55 can be welded into position if desired. The mounting bracket 55 is U- shaped, and has a top wall on which a plurality of hydraulic control valves are fixedly mounted. This protects the valves and holds them securely. As shown, there are six control valves, one corresponding to each of the control handles, and these valves are mounted to be aligned with the respective links 48B-53B. The valves in turn are numbered 48C-53C and are of usual design comprising four way hydraulic control valves that will control fluid under pressure for operating hydraulic motors.

The valves receive pressure from a source of fluid under pressure illustrated schematically at 56, and each is separately connected into the pressure source 56. Of course the suitable reservoir is used in the usual manner. The hydraulic system or pressure source 56 is a normal pump and reservoir used with hydraulic components of existing motor graders driven from the engine of the grader itself.

Each of the hydraulic valves in turn controls a separate hydraulic motor. For example, the valve 48C controls the hydraulic motor 48D for the right lift gear box 26, and the valve 49C controls flow of fluid under pressure flow to a motor 498 for the left lift gear box 26. The valve 50C controls flow to the scarifier drive motor illustrated at 50D, and this is coupled to drive the gear box 36 which is used for raising and lowering the scarifier (not shown).

The valve 52C controls the flow of fluid under pressure to a lateral shift hydraulic motor 52D which drives a shaft 57 that in turn-drives the gear box 20 operating for the lateral shift of the blade 16 and circle frame 15.

The valve 53C controls a hydraulic motor 53D that drives through the shaft 33 to the wheel lean gear box 34 to control the leaning of the front wheels which is necessary for grader operation.

Thus, the operation of the various control levers is a simple operation that directly controls hydraulic valves external of the operators compartment to operate hydraulic motors that in turn operate through the normal mechanical gear boxes to the various movements that are standard on road graders. The unit can be installed quickly into any standard road grader to replace the mechanical clutch controls that are now standard on many road graders. The valves are located externally of the operators platform so that any heat generated by the valves is kept out of the operators immediate area.

The valve spools themselves have to be able to withstand high loads because of the levers 48 are quite long and a great deal of force can be exerted on the particular valve spools. In order to function in the manner using the long control levers, each of the valves is modified as shown in FIGS. 4 and 5. For example, a typical valve 48C is mounted onto the cross member of frame 55, with cap screws or the like. The valve 48C has a valve spool 60 that operates in the valve body in the usual manner. The spool 60 is connected to the link 48B with a pin so that the link will move the spool in and out in directions indicated by the double arrow 61 to the respective actuated positions of the valve spool. The spool 60 is provided with an external stop for both directions of travel. A roll pin or spring pin 62 is mounted through the spool and is positioned so that when the valve spool 60 is operated in a first direction moving the pin 62 toward the valve body (this would be pulling the top of the control handle 48 toward the rear) the spring pin 62 will contact the face 63 of the valve body to stop the spool in its actuated position very positively and with a substantial amount of surface area bearing against the pin so that no damage will be caused to the internal parts of the valves nor to the internal spool centering springs supplied with the valve. When the spool 60 is actuated in opposite direction, the spring pin 62 in turn strikes a stop ring washer 64 that is mounted to the valve body with cap screws 65 extending through spacers 66 that space the stop washer 64 outwardly from the end surface 63 of the valve body a sufficient distance so that the spring pin 62 will strike the surface of the washer and positively stop the spool when the spool has been moved outwardly to its actuated position.

Thus a very positive external stop is provided and so that even when the high mechanical advantage of the levers 48-53 is utilized, the valves corresponding to these levers will not be damaged. The stop mechanism illustrated in connection with the valve 48C is used with the spools of all of the valves. The showing is typical of the rest of the valves.

The hydraulic operation of the grader of course is.

smooth, and the control handles are not subject to kick-back" or excessive load as in mechanically operated devices, and in general makes the operation of the road graders much simplier and easier. The entire gang of control handles is mounted on a common support, and can easily be serviced. The shaft 47 can be removed for service, and of course the valves themselves are out in the open where they can be serviced and connected conveniently. The bracket member 46 also has a flat top wall 46A. The control handles extend through openings in this top wall. The top wall 46A may be used as a mounting wall for various components of the grader.

The motors 48D and 49D can be connected directly to the input housings of the gear boxes 26 which are used with jaw clutch controls by reversing these input housings and connecting the motors directly. The input housings are indicated at 26A and 26B respectively for the right and left gear boxes. These are the standard input housing supplied with the graders presently being sold, and the mere reversal of these gears make the addition of the hydraulic motors very simple. The hydraulic motor output shafts merely have bevel gears thereon which drive to the input worms for the normal worm gear sets in housings 26. The gear sets in turn drive the lift shafts 24.

The hydraulic motors used are conventional hydraulic motors which give high torque at low rpm, and are satisfactory for this type of operation.

The valve spools are spring centered to their off or neutral positions by internal springs acting on the valve spools.

What is claimed is:

1. In a control system for operating road maintenance equipment utilizing a plurality of drive units for operating devices on said equipment, said devices normally being driven from manually controllable mechanical clutches, the improvement comprising a mounting bracket, a mounting shaft on said bracket, a plurality of control handles pivotally mounted to said mounting shaft, a separate link connected to each of said control handles, said links being axially movable upon movement of said control handles, a separate hydraulic control valve controlled by each of said links, and a hydraulic motor controlling each of said drive units, said hydraulic motors being controlled by operation of said control valves through said control handles and said links, said control valves comprising spool operated valves, each having a valve body and a valve spool with an exterior end portion outside the valve body, means coupling each of said links to a respective valve spool, and heavy duty mechanical stop means on each of said control valves comprising a separate stop pin on an exterior end portion of each of the valve spools, and a separate stop ring for each valve spool,

means to mount said stop rings with respect to said valve bodies and in position spaced outwardly from said stop pins with the valve spools in a neutral position, said stop pins moving to position to engage the respective valve body when a valve spool is actuated in a first direction from its neutral position, and said stop pins moving to a second position to engage an associated stop ring when a valve spool is actuated in a second direction from its neutral position.

2. The combination as specified in claim 1 wherein each of said stop rings comprises an annular ring surrounding the valve spool with which it is associated, I

said means to mount said stop ring comrising spacer means positioning said stop ring outwardly from the end of the respective valve body a preselected distance, and means to attach the stop ring with respect to said respective valve body through said spacer means.

3. The combination as specified in claim 1 wherein there are at least six separate control handles mounted onto said mounting shaft, each of said handles being pivotally mounted on saidmounting shaft.

cle frame. 

1. In a control system for operating road maintenance equipment utilizing a plurality of drive units for operating devices on said equipment, said devices normally being driven from manually controllable mechanical clutches, the improvement comprising a mounting bracket, a mounting shaft on said bracket, a plurality of control handles pivotally mounted to said mounting shaft, a separate link connected to each of said control handles, said links being axially movable upon movement of said control handles, a separate hydraulic control valve controlled by each of said links, and a hydraulic motor controlling each of said drive units, said hydraulic motors being controlled by operation of said control valves through said control handles and said links, said control valves comprising spool operated valves, each having a valve body and a valve spool with an exterior end portion outside the valve body, means coupling each of said links to a respective valve spool, and heavy duty mechanical stop means on each of said control valves comprising a separate stop pin on an exterior end portion of each of the valve spools, and a separate stop ring for each valve spool, means to mount said stop rings with respect to said valve bodies and in position spaced outwardly from said stop pins with the valve spools in a neutRal position, said stop pins moving to position to engage the respective valve body when a valve spool is actuated in a first direction from its neutral position, and said stop pins moving to a second position to engage an associated stop ring when a valve spool is actuated in a second direction from its neutral position.
 2. The combination as specified in claim 1 wherein each of said stop rings comprises an annular ring surrounding the valve spool with which it is associated, said means to mount said stop ring comrising spacer means positioning said stop ring outwardly from the end of the respective valve body a preselected distance, and means to attach the stop ring with respect to said respective valve body through said spacer means.
 3. The combination as specified in claim 1 wherein there are at least six separate control handles mounted onto said mounting shaft, each of said handles being pivotally mounted on said mounting shaft.
 4. The combination as specified in claim 1 wherein said maintenance equipment has an earth working blade and a laterally shiftable circle frame rotatably mounting said blade, and wherein said hydraulic motors operate drive units for lifting said earth working blade of said maintenance equipment, and drive units to rotate the circle frame, and to laterally shift the circle frame. 